Shares of SmileDirectClub, Inc., the much-hyped orthodontics disruptor, fell 28% Thursday after pricing at $23 each, above the indicative range of $19 and $22 per share.

That is by far the worst first-day performance for an IPO selling $500 million in shares or more since at least 2000, according to Dealogic. In a distant second place was Moderna, which fell 19% on its first day of trade last December. Among the other stinkers on the list is Uber Technologies, Inc., which fell 8% on its first day of trade in May.

SmileDirectClub, which sells teeth aligners by mail that don’t require orthodontists visits and are far less expensive than traditional braces, has been a battleground stock even before listing. One firm that was highly skeptical of the deal was Renaissance Capital.

“[B]ecause the clear aligners are not differentiated in any substantial way, the company has had to increase spending on sales and marketing to stay ahead of a growing pool of competitors, making the path to profitability unclear,” Renaissance Capital wrote in a client note dated September 5. “Although the management team has experience running direct-to-consumer businesses, this deal is structured to enrich the founding family and insiders and leave control in their hands, and the proposed valuation does not give new investors anything to smile about.”

JPMorgan Chase & Co. and Citigroup, Inc. were the lead managers on the deal.